In the Character Card Library, you can filter by Retail Package. Then you can easily see the existing Heroes, Bosses, Pets, and Spawn Points. For the spawn points, just check the spawn point card for the list of models. Remember that you have Bramble Knight spawn point two times in the Forgotten King set.

The only things where the library does not really help are the number of treasure chests and creeps. There should be 6 Rabid Squirrels, 3 Boo Bootys, and 5 regular treasure chests. I may be off by one on the treasure chests, but that should be all.